1. Field of the Invention
The present invention relates to wireless communications, and more particularly, to an apparatus and method of transmitting ACK/NACK (acknowledgement/negative ACK) information in downlink and an apparatus and method of receiving the ACK/NACK information.
2. Discussion of the Related Art
Recently, wireless communication systems are widely developed to provide various kinds of communication services including audio communications, data communications and the like. Generally, a wireless communication system is a kind of a multiple access system capable of supporting communications with multiple users by sharing available system resources (e.g., bandwidth, transmission power, etc.). For instance, multiple access systems include CDMA (code division multiple access) system, FDMA (frequency division multiple access) system, TDMA (time division multiple access) system, OFDMA (orthogonal frequency division multiple access) system, SC-FDMA (single carrier frequency division multiple access) system and the like.